Propulsive blasting explosive



Patented May 15, 1923.

UNITED STATES PATENT OFFICE.

I ARCHIIBALD JACKSON STRANE, OF ST. PAUL, MINNESOTA, ASSIGNOR TO ATLAS POWDER COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

PROBULSIVE BLASTING EXPLOSIVE.

Io Drawing. Application filed June 7,

To all whom it may concern:

Be it known that AROHIBALD JACKSON STRANE, citizen of the United States, residin at St Paul, in the county of Ramsey and tate of Minnesota, has invented certain new and useful Improvements in Propulsive Blasting Explosives, of which the following is a s cification.

This applicatlon is a continuation in part of m application Serial Number 512,327,

filed ovember 2, 1921.

My invention relates partcularly to modified black blasting powder suitable for use in all cases where ordinary black blasting powder may be suitably used.

The ob'ect of my invention is to provide black blasting powder of increased stren h and blasting effectiveness and incidenta ly to provide a means of profitably utilizing waste, surplus or salvaged nitrocellulose smokeless powder, although this sort of nitrocellulose powder is not essential to my invention since, I may, at my option and if trade conditions warrant it, colloid nitrocellulose for the express and primary purpose of making my modified black blastin powder.

t should be expressly understood that -my invention is not concerned with black gun owder, i. e., with black powder in its app ication as a propellant in firing arms, ns, mortars, and implements of this type. use the term black blasting powder for my product to indicate this distinction.

Neither is it concerned with high or detonating blasting explosives. Explosives may be classified, as will be understood by those skilled in the art, as high and low. Low explosives are suitably initiated by the mere application of flame or heat and their action may be termed rapid combustion with the development or" a propulsive or pushing effect on the material to be blasted. High explosives must be initiated by means of a blasting cap or equivalent for efl'ectiveness and their action may be termed detonation ith the development of a disruptive or shattering efiect on the 1922. Serial No. 566,555.

material to be blasted. The above descriptions and distinctions are. of course relative, but leave no doubt in the mind of any one familiar with explosives to any extent as regards my meaning and intent.

My invention deals with black blasting powder as a low or propulsive blasting explosive.

A usual practice in manufacturin black blasting powder consists in keeping t e compositions constant and varying the blastmg characteristics b varying the granulation sizes-the smal er the sizes of the individual particles or grains the more rapid the rate of burning and consequently the more intensive the effect on the material to be blasted. 'Phus, there exist the usual grades FFFF, FFF, FF, F, C and CC, arranged according to increasing size of grains, but the chemical and ph sical composition practically constant. 11 addition to increasing or decreasing the intensiveness of the efiect of black blasting powder by varying the granulation, the same condition may be achieved to a greater or lesser degree by varying the degree of fineness of the individual ingredients, the extent of incorporation, the density and the moisture content. However, the modern powder represents substantially the best that can be practically and economically accomplished along these lines. Yet there remains another consideration-namely; the effect on properties of varying the chemical composition. Confined to the usual ingredients potassium nitrate 'or sodium nitrate, charcoal and sulphur, modern powder represents practically'the best that can be done. Many solid explosive compounds might be suggested that might, theoretically, be added to black blasting powder to a greater or less extent to increase its strength, but they 0 are practically all open to serious objection on some such ground as cost, safety, hygroscopicity, etc.

I have now discovered that colloided nitro-cellulose of the character of straight niservice powder, for instance) or of nitrocellulose-nitroglycerine smokeless powder (cordite, for instance), when suitably granulated or when in suitable original concorn and wheat. In preparmg my powder I proceed according to the following examples. Assuming, for instance, 5 Amer- ,ican service powder, I disintegrate it by any suitable means which possesses a proper degree of safety and which furnishes a disinte rated product of which the ma'ority of the partlcles are within the -granulation sizes commonly used for black blasting powder. Next, the disintegrated product is dried, provided wet disintegration has been used, and the dried product is granulatedand graded to the proper size on the usual black blasting powder sizing or grading screens. As a result, I have colloided nitrocellulose powder se arated approximately accordin to the F FF, FFF, FF, etc., granulatlon of black blasting powder and may readily make any desired mixtures by any ordinary mechanical means. I find, that, if the granulations of both types of explosives are ke t approximately the same, there is practica ly no tendency for one to se arate or segregate from the other.

y way'of another example, there are certain smaller sizes of smokeless powder which in their originalcondition are suitable for admixture with one or the other grades of blackblasting powder without disintegration. a

Regarding the efi'ectiveness of my invention I will show a set of ballistic results obtained by mixin various amounts'iof suitablygranula I straight nitrocellulose smokeless .powder with regular FFFF black blasting powder. I

Per cent rrrr black 5mm}; mimic blasigpg powder. pressures.

, Tm per It a. 100 12 H- 5 6; 2 90 10 8. 28 so no 10. 74

Further, numerous trials under actual blasting conditions have also indicated the great efiectiveness of my invention.

There is a point of especial and novel interest which I desire to point out. If a blaster has used, for instance, FF black blasting powder and changes. to FFF he obtains greater apparent explosive strength solely because he has a more rapidly burning powder. With equal weights of charges, there is no more gas or heat evolved in one case than in the other, it is merely that, in the latter case, the gas and heat are evolved in a shorter time. On the other hand, black blasting powder made according tomy invention gives greater strength without increased rapidity of burning, because smokeless powder is slower burning than black blasting powder, granulations being approximately equal. The black blasting powder serves to bring the rate of burnmgof ing the-tremendous quantities of cheap, surplus smokeless powder remaining from the world war the economic applicability of my invention is evident/ surplus smokeless powder are stored in this country and. that this powder will probably be sold for one cent per pound or less. Manifestly any process which renders these en0r-.

mous stocks available for constructive comniercial pu oses 'is of value. Havmg escribed my lnventlon what I claim 1s:

1. A propellent blasting explosive consist- .2; A blasting explosive consisting of a mixture of granulated black blasting powder and suitably granulated American service smokeless powder, in which mixture each individual gram is either all black blasting powder or all smokeless powder.

3. A blasting explosive consisting of 90% 'FFF black blasting powder and 10% suitably colloided nitrocellulose powder of a granulation approximately like that of the FF black blasting owder.

4. A blasting exp osive consisting of 80 100 It is a fact that enormous quantities ofto 90% granulated black blasting powder each individual grain is either all black and 20 to 10% suitably oolloided nitroeellublasting wder or all smokeless powder. 10 lose powder. In testimony whereof I aflix my signature 5. A blastingziglosive consisting of '80 to in the resenoe of two witnesses.- I 90% granular 1 blasting powder ,and' 20*. AR HIBALD JACKSON STRANE.

to 10% of granulated service smokeless w-' Wi: der wherein the sizes of the grains of th E. Ron S'mnm, are approximately the "same and wherein CATHERINE 

